1. Field of the Invention
The present invention relates to a dishwasher, and more particularly to a drying duct for discharging the hot, humid and pressurized air generated during the drying processes.
2. Description of the Prior Art
Generally, a dishwasher is composed of shelves for fixing up the dishes in the tub, a cleansing motor enabling the cleansing water to be jetted to the dishes, cleansing nozzles jetting the cleansing water to the dishes in various directions and then cleansing the dishes, a blowing fan infusing the outside air into the tub, and an air outlet formed to discharge the hot, humid and pressurized air in the tub out into the outside.
This kind of conventional dishwasher is designed to clean the dishes laid on the shelves with the cleansing water jetted to the dishes in various directions by the cleansing motor and nozzles when the power is applied on the dishwasher with dishes on the shelves.
Furthermore, when the cleaning process is finished in the dishwasher, dishes are dried by a heater and at the same time a blowing fan is operated for improving the drying efficiency, so that outside air is infused into the dishwasher.
However, owing to the outside air being infused into the dishwasher and, the heating temperature being generated during the drying processes of dishes, the infused outside air is combined with humid air produced by the cleansing water inside the dishwasher, which are all thereafter discharged to the outside through the discharge orifice at the same time.
In other words, in order to increase the washing efficiency of dishwasher, the dishes are heated by the heater and simultaneously are jetted with water by the nozzles. And at this moment, hot and humid air fills the inner area of the dishwasher, which increases the pressure inside the tub. Then, the blowing fan is operated to maintain the same pressure in the tub as the atmospheric pressure and simultaneously to increase the drying efficiency, which thereby discharges the hot and humid air out to the outside.
However, as explained above, in order to upgrade the washing efficiency, when the dishes are washed or dried with the hot washing water in a dishwasher, the hot and humid air is discharged to the outside. In this case, the hot and humid air being discharged becomes condensed water due to the temperature difference and flows down along the outside wall of the dishwasher, causing erosions in and outside the dishwasher, or in case the condensed water seeps into the inside of a dishwasher, damage to the inner components and electric leakages can occur.
Furthermore, the hot, humid and pressurized air and condensed water being generated from the dishwasher can create a problem of adversely affecting electric and other surrounding appliances.
In order to solve said problems, many techniques to retrieve the discharging vapor and humidity are known by the artisan, and is represented by Japanese Laid-Open Utility Application No. SHO-57/112765, wherein an exhaust duct discharging the hot and humid air from the inside of dishwasher to the outside is provided, and a dewing apparatus is mounted on said exhaust duct, which retrieves a condensed water portion of the hot humid air being discharged.
Also, Japanese Laid Open Patent Application No. HEI-2/218328 discloses a technique wherein air ventilation routes are formed in various openings installed inside the tub. The vapors in the tub are routed through said air ventilation routes by the blowing fans, by which the vapors are condensed into condensed water and retrieved by way of a heat exchanger in between the waters underneath the lower area of the tub.
However, the former dishwasher (57-112765), being equipped with dewing apparatus at the air outlet of the conventional dishwasher, involves a difficulty in installing the dewing apparatus to the exhaust duct in addition to the inability of completely instantly condensing to condensed water the hot and humid air being discharged to the outside. The latter dishwasher (2-218328) having a closed tub, has to be provided with a separate discharge orifice to maintain the same pressure in the tub as the atmospheric pressure. The latter dishwasher also has the problem of lowered retrieving efficiency of vapor and longer drying time due to hot humid conditions in the tub when the vapor is condensed by a heat exchanger in between air circulating routes and supplied water.
Also, the condensing effect made by the contact with hot humid air circulating through the air circulating routes and the waters supplied to the inner lower area of dishwasher, in the case of the latter dishwasher, deteriorates efficiency-wise as time elapses, or the hot and humid air can not be condensed as the temperature of the water supplied to the dishwasher soars up, which causes the hot and humid air being generated by the dishwasher to be discharged through separate discharge orifice away from the air circulating routes.